Artificial Blood for Emergency Transfusions: Guided by computer-assisted molecular modeling, we design and synthesize novel polyfunctional organic reagents to cross-link cell-free hemoglobin. These modified hemoglobins will potentially serve as substitutes for whole blood for emergency transfusions, and would require no typing or cross-matching, be free of bacteria or viruses, and storable as a dry powder for indefinite periods of time. The cross-linking is anticipated to prevent the otherwise rapid renal elimination of cell-free hemoglobins, while also decreasing the latters oxygen affinity, so as to afford adequate oxygen and carbon dioxide transport from lungs to tissues and vice versa. To accomplish the above goal, we need an access to high mass analysis in the range of 32,000-33,000 by MALDI-MS. Each of the four hemoglobin subunits, ?1, ?1, ?2, ?2, weighs approximately 16,000 Daltons. When cross-linked, they form a dimer of ?32,000 Daltons. Therefore, MALDI-MS would enable us to conveniently a) analyze the cross-linking patterns, and b) in conjunction with tryptic digestion, map regions where cross-linking has occurred.